Steerable catheter with rapid exchange lumen

ABSTRACT

A medical device for advancement over a guidewire includes a number of lumens therein including a working channel lumen, one or more control wire lumens, and a guidewire lumen. A flexible support within the device includes a number of interlocking elements that resist longitudinal compression, transfer rotational torque, and can bend side to side. The flexible support also includes a slot that is aligned with the guidewire lumen. An outer jacket includes a perforation, slot, slit, or thinned area that is aligned with the slot in the support member and the guidewire lumen in order to allow a device such as a guidewire to be removed from the guidewire lumen and through the support member.

TECHNICAL FIELD

The disclosure relates to medical devices in general, in particular tosteerable devices for use with a guidewire.

BACKGROUND

As an alternative to performing more invasive medical procedures, manyphysicians are performing examinations and/or therapeutic procedures invivo with catheters or other devices. Such devices are generally routedfrom outside the patient to an area of interest through a small openingin the skin or through a body orifice. Such devices often include one ormore lumens by which additional tools, medicines, and the like, can bedelivered to a site in order to perform a desired task.

In order to route a catheter to its desired location, many proceduresrequire the use of a guidewire. The guidewire is first advanced by thephysician to the point of interest and then left in place to serve as arail over which additional devices can be routed in order to guide themto the desired location.

FIG. 1 shows an example of a conventional guidewire 10 and a catheter 20positioned over the guidewire. In many procedures, it is desirable toleave the guidewire in place while one catheter is exchanged foranother. Therefore, the proximal end 12 of the guidewire 10 is fixedwhile the catheter 20 is removed from the patient. In order to maintaina handle on the proximal end 12 of the guidewire 10, it is necessarythat the portion of the guidewire that remains outside the patient belonger than the length of the catheter 20. Therefore, acatheter/guidewire system such as that shown in FIG. 1, requires the useof long guidewires that can be cumbersome to manipulate and can clutteran operating room.

To address the issues associated with changing catheters over longguidewires, many catheters include so-called “rapid exchange” lumens. Asshown in FIG. 2, a rapid exchange catheter 30 includes an opening 32 onthe sheath of a catheter and a slot 34 that extends along the length ofthe catheter through which a guidewire 40 can be pulled. To exchange thecatheter 30 for another device while maintaining the position of theguidewire 40 in the body, the catheter 30 is stripped off the guidewire40 by pulling it through the slot 34. A new catheter or device can berouted over the guidewire 40 by inserting the proximal end of theguidewire 40 into an opening of a guidewire lumen at the distal end ofthe new device and advanced such that the proximal end of the guidewireexits the opening 32. The opening 32 may be positioned towards theproximal end of the catheter or may be located more towards the distalend.

While rapid exchange catheters and devices have been developed for manyprocedures, they have not been adapted for use with steerable cathetersor catheters that are required to transmit torque from the proximal tothe distal end of the catheter. Such devices often include a wire braidto increase column strength and transfer rotational torque. However,cutting this braid to allow the removal of the guidewire results in thebraid becoming unraveled or frayed in a manner that can compromise theconstruction and performance of the catheter.

Because steerable devices are becoming increasingly used to navigatethrough the patient's body, there is a need for a mechanism toincorporate the advantages of a rapid exchange guidewire lumen withdevices that are steerable and/or can transmit torque.

SUMMARY

To address the problems discussed above, the present disclosure isdirected to a rapid exchange type medical device that can be steeredwithin the body using one or more control wires and/or can transmittorque from the proximal end to the distal end.

In one embodiment, the device is a catheter that includes an outerjacket and a support member positioned therein that resists longitudinalcompression and transfers rotational torque from the proximal end of thecatheter to the distal end. In one embodiment, the support member has anumber of aligned rings that are joined together with hinges. Inaddition, the support member includes a longitudinally extending slotalong a portion of the circumference of the rings. The slot in thesupport member is aligned with a guidewire lumen in the catheter and acorresponding slot, perforation, or other opening in the outer jacketthrough which a guidewire can be removed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a conventional catheter and guidewire;

FIG. 2 illustrates a rapid exchange type catheter and guidewire;

FIG. 3 illustrates one embodiment of a rapid exchange medical device;

FIG. 4 illustrates one embodiment of a flexible support;

FIGS. 5A and 5B illustrate the flexible supports made from flat sheetsof material;

FIG. 5C illustrates another embodiment of a flexible support;

FIG. 6 illustrates a guidewire and a rapid exchange catheter;

FIG. 7 illustrates a multiple lumen extrusion including a guidewirelumen;

FIGS. 8A, 8B, and 8C illustrate various embodiments of an exterioropening in an outer jacket of a catheter; and

FIG. 9 illustrates one embodiment of a steerable, rapid exchangecatheter.

DETAILED DESCRIPTION

As will be described in further detail below, the present disclosure isdirected to a rapid exchange catheter or other medical device that canbe steered within a patient and/or can transmit rotational torque alongits length. Although the embodiments disclosed are configured ascatheters, it will be appreciated that the device is useful in anymedical instrument that is designed to be used with a guidewire or othertool to be removed from an outer sheath. FIG. 3 illustrates oneembodiment of a steerable catheter including a rapid exchange guidewirelumen. The catheter 50 has a distal tip 52 with openings to a number oflumens within the catheter. In the example shown, the distal tip 52includes an opening 54 to a working channel lumen and an opening 56 to asecond lumen, which may be used to route a fiber optic bundle or othertool within the catheter. In addition, the distal tip includes anopening to a guidewire lumen 58 that allows the rapid exchange of thecatheter 50 over a guidewire as will be explained in further detailbelow.

As better shown in FIG. 4, a flexible support 60 extends from the distaltip 52 towards the proximal end of the catheter 50. The flexible support60 serves to increase the column strength of the catheter 50 and totransfer torque along its length. In one embodiment, the flexiblesupport 60 has a number of axially aligned rings 62, 64, 66, etc., eachhaving an outer edge that extends substantially around the circumferenceof the catheter 50. Adjacent rings, for example, ring 62 and ring 64,are secured to one another by one or more hinges 70. Between eachadjacent pair of rings, the hinges 70 are staggered. For example, in oneembodiment, a pair of rings may be secured together with four hingespositioned at 0°, 90°, 180°, and 270° around the circumference of therings. An adjacent pair of rings may be secured together with hingespositioned at 45°, 135°, 225°, 315°, etc. It will be appreciated thatfewer or more hinges could be used to join adjacent rings. For example,each ring could be joined to an adjacent ring with two hinges wherebythe hinges are adjacent rings are offset by 90°.

In addition, the flexible support 60 includes a longitudinally extendingslot 72 formed by a gap in each of the rings and extending along thelength of the support. The slot 72 is aligned with the guidewire lumen58 within the catheter. As shown in FIG. 3, an outer jacket 82 may coverthe flexible member 60. The outer jacket 82 may be made from or coatedwith a lubricious material, such as PTFE, to facilitate passage of thecatheter within a patient's body.

The outer jacket 82 preferably includes a slit, perforation, slot or thelike positioned over the area of the longitudinally extending slot 72 inthe flexible support 60 and the guidewire lumen 58. In this manner, aguidewire that is positioned within the guidewire lumen 58 can be pulledthrough the outer jacket 82 and the slot 72 within the flexible support60 in order to peel the catheter 50 off the guidewire.

The flexible support 60 may be made from a hypotube made from a materialsuch as stainless steel, wherein the rings and hinges are cut with alaser, chemically etched, or ground into the hypotube. Alternatively,the support member 60 can be molded from plastic or other suitablematerials.

As an alternative to making the support member 60 out of a hypotube, thesupport member 60 can be made from a flat sheet of material such asstainless steel and rolled or formed into a final shape. As shown inFIG. 5A, a flexible support 90 includes a number of band elements 92,94, 96, 98 that are joined with hinges 100 extending generallyperpendicular to the length of the bands. In the embodiment shown, thehinges 100 between adjacent pairs of bands are staggered or offset fromeach other. The flexible support 90 can be stamped, molded, etched, orlaser cut from a piece of flat material before being rolled or formedinto a final shape. Although the bands are shown as being joinedtogether with four hinges in the embodiment shown in FIG. 5A, this isnot required. FIG. 5B illustrates an embodiment wherein adjacent bandsare joined together with two hinges 102. Each pair of hinges 102 isoffset, for example, by 90 degrees, with respect to an adjacent pair ofhinges. Once rolled or formed into a tubular shape, each of the bands92, 94, 96, 98 become the rings of the flexible support. The oppositeedges of the bands can be spaced apart to form the slot that is alignedwith the guidewire lumen. Alternatively, the opposite edges can bejoined by welding or the like and a new slot cut therein to allowpassage of the guidewire.

FIG. 5C illustrates yet another embodiment of a flexible support 120. Inthis embodiment, the support comprises a cylindrical tube havinginterlocking elements 122, 124, etc., that are joined by a pattern ofcuts 125. The flexible support 120 resists compression along its length,but transfers rotational torque when incorporated into the catheter. Inaddition, the flexible support includes a slot 130 that allows passageof a guidewire out of the guidewire lumen. The flexible support 120 canbe made in a manner similar to that used to make medical stents.

FIG. 6 illustrates a catheter 50 routed over a guidewire 140. At theproximal end of the catheter is an opening 142 that allows access to theguidewire lumen within the catheter. A slot 144 extends from the opening142 towards the distal tip 52 of the catheter and is positioned over theguidewire lumen. In the embodiment shown, the guidewire 140 has a distalend that extends through the opening at the distal end of the guidewirelumen and a proximal end that extends out of the opening 142 in thecatheter body. To remove the catheter 50 from the guidewire 140, theguidewire 140 is pulled through the slot 144 extending along the lengthof the catheter. Because the flexible support 60 has the slot 72therein, the guidewire can be pulled through outer jacket 82 to exchangethe catheter.

FIG. 7 illustrates one embodiment of an extrusion used to form thevarious lumens in the catheter. As indicated above, the extrusion 150may include a working channel lumen 152, a second lumen 154 that can beused to route an optical fiber or other tools through the device. Inaddition, one or more additional lumens 156 may be provided to passtools, gases, or liquids through the device. In addition, the extrusion150 includes a guidewire lumen 160. The guidewire lumen 160 is generallyU-shaped such that the lumen has one side open along the circumferenceof the extrusion 150.

In the example shown in FIG. 7, the extrusion 150 also includes a numberof control wire lumens 162, 164, 166, 168 through which correspondingcontrol wires 170, 172, 174, 176 can be routed. Each of the controlwires 170-176 has a distal end that is secured at or adjacent the distalend of the catheter and can be selectively tensioned in order to bendthe catheter in a desired direction. Although the example shown usesfour control wires, it will be appreciated that directional control ofthe device can be obtained with more or fewer control wires if desired.

In accordance with one embodiment, the flexible support 60 is positionedover the extrusion 150 so that the slot 72 is positioned over theguidewire lumen. The outer jacket 82 is then placed over the flexiblemember by, for example, an extrusion process or heat reaction, dipping,etc. The flexible support 60, therefore, is sandwiched between theextrusion 150 and the outer jacket 82.

FIGS. 8A-8C illustrate various embodiments of an entrance to theguidewire lumen through the outer jacket 82 of the catheter. In theembodiment shown in FIG. 8A, the entrance comprises a perforated slot180 extending along the length of the catheter or portion thereof. Inthe embodiment shown in FIG. 8B, the entrance to the guidewire channelincludes a slot 182, wherein the edges of the slot remain some distanceapart. In the embodiment shown in FIG. 8C, the entrance to the guidewirechannel along the length of the catheter comprises a slit 184 whereinthe edges of the slit abut each other. In yet another embodiment, thearea over the guidewire channel may be completely sealed by the outerjacket of the catheter. However, the outer jacket may be thin enough inthis area such that a guidewire can be pulled through the outer jacket.In yet another embodiment, the outer jacket can be coextruded with asofter material along its length to provide a weaker wall through whicha guidewire can be pulled.

FIG. 9 illustrates one embodiment of a steerable catheter systemincluding a rapid exchange lumen. The catheter 200 includes a handle 202at a proximal end. The handle 202 has a pair of controls 204, 206 thatselectively tension or release pairs of control cables positioned withinthe catheter in order to steer the distal tip in the desired direction.Extending distally from the handle 202 is a flexible catheter 208, inaccordance with any of the above-described embodiments, that is insertedinto the patient. The catheter 208 includes a rapid exchange lumen 210that allows the catheter 208 to be easily removed from a guidewire (notshown) by pulling the guidewire through the side of the rapid exchangelumen 210 in order to exchange the catheter for another one over theguidewire.

While the preferred embodiment of the device has been illustrated anddescribed, it will be appreciated that various changes can be madetherein. It is, therefore, intended that the scope of the invention bedetermined from the following claims and equivalents thereof.

1. A medical device comprising: a body having a proximal end, a distalend and a number of lumens therein, the lumens including: a workingchannel lumen; at least one control wire lumen; a guidewire lumen; and aflexible support having a number of rings that extend circumferentiallyaround the device, hinges that join adjacent pairs of rings together anda slot extending through the rings and along a length of the flexiblesupport whereby the slot is aligned with the guidewire lumen.
 2. Themedical device of claim 1, wherein the catheter body has an outer jacketand the support is positioned between the lumens and the outer jacket.3. The medical device of claim 2, wherein the lumens are formed in anextrusion positioned within the catheter body, and the flexible supportis positioned between the extrusion and the outer jacket.
 4. The medicaldevice of claim 2, wherein the outer jacket has a slot aligned with theslot in the flexible support and the guidewire lumen.
 5. The medicaldevice of claim 2, wherein the outer jacket has a slit aligned with theslot in the flexible support and the guidewire lumen.
 6. The medicaldevice of claim 2, wherein the outer jacket has a reduced thickness inan area over the slot in the flexible support.
 7. The medical device ofclaim 2, wherein the outer jacket includes a softer material in an areaover the slot in the flexible support.
 8. A medical device, comprising:an elongated body having a proximal end, a distal end, a flexiblesupport extending along at least a portion of the length of the body anda side lumen, wherein the flexible support includes a number ofinterlocking elements that resist longitudinal compression of theflexible support and transfer rotational torque, the flexible supportfurther including a slot positioned over the side lumen such that adevice can be removed from the side lumen through the slot in theflexible support.
 9. The medical device of claim 8, wherein theelongated body comprises an outer jacket and the flexible support ispositioned between the side lumen and the outer jacket.
 10. The medicaldevice of claim 9, wherein the outer jacket comprises a slot alignedwith the slot in the support member.
 11. The medical device of claim 9,wherein the outer jacket comprises a slit aligned with the slot in thesupport member.
 12. The medical device of claim 9, wherein the outerjacket comprises a thin area aligned with the slot in the supportmember.
 13. The medical device of claim 9, wherein the outer jacketcomprises a softer material aligned with the slot in the support member.14. The medical device of claim 8, wherein the side lumen is sized toreceive a guidewire therein.
 15. The medical device of claim 8, furthercomprising one or more control wires therein that are selectivelytensioned to control the orientation of the distal end.